Over the years, farming efficiency has dictated that the machinery used become larger and larger. For example, tool bars that have agricultural implements attached thereto, such as planters, chisel plows, cultivators, etc. have evolved into very lengthy devices which typically fold for transport down the road and which cover many rows of crops during use. This allows the field to be worked in as few passes through the field as possible, thereby increasing efficiency of the farming operation.
These long tool bars work extremely well on level land but when the terrain becomes uneven, certain of the earth working implements will be higher from the surface of the ground than others if the tool bar itself is straight and rigid during field working operations. That is the reason that flexible tool bars have been developed. By flexing the tool bar in the middle, or at other places along the lengths if desired, the planter units or other earth working implements attached to the tool bar can be maintained approximately the same distance from the top of the ground being worked along the entire length of the tool bar. Where the land has been terraced, for example, it has been determined that a two-part tool bar pivotally attached at the center thereof works very nicely so that if the pivot is maintained at the top of the terrace by the tractor, then one side of the tool bar can hang down over one side of the terrace and the other side of the tool bar can hang down over the other side of the terrace to maintain the aforementioned approximate consistency of distance between the earth working implements attached to the tool bar and the top of the ground.
One of the problems associated with a flexible tool bar of the type mentioned above is that when it is desired to transport the implement from place to place or to merely turn around at the end of a field to make another pass through the field, the tool bar must be held straight and rigid or the ends thereof will hang down and contact the ground in an undesirable fashion. Furthermore, the flexing will cause bouncing and instability in a transport situation.
Because of the need to hold the tool bar rigid during transport and turn around situations, one manufacturer has utilized a rigid turn buckle arrangement which mechanically can be engaged or disengaged and manually adjusted as to length to hold the tool bar from flexing when flexing is not desired. A major problem with such arrangement is that it is quite time consuming and inefficient at a time when economics demand that farming be efficient.